Immunotherapies are forms of treatment where the immune system of an organism is influenced. The immunomodulation may serve for an attenuation of the immune system such as after transplantations and to avoid a rejection reaction, but also for an immunostimulation, i.e. an enhancement of the natural immune response. The active agents of an immunotherapy are generally identified as immunomodulators. Immunomodulators may be, therefore, immunostimulants or immunoinhibitors. An example of a prominent immunostimulant is the interferon which is used in the therapy of hepatitis C diseases. Also plant-based immunomodulators are described, for example extracts from the hemp plant or the purple cone flower.
For the malign melanoma already different immunomodulating substances exist which are used in the clinic and which modulate the activity of the natural killer cells (NK cells). Therefore, for such purpose interferon α is used in the adjuvant melanoma therapy in the stages II and III or interleukin 2 (IL-2) is used in the treatment of the metastasizing melanoma in the stage IV.
Also in other diseases immunomodulating substances are used, for example pegylated interferon for the treatment of hepatitis C or interferon β for the treatment of multiple sclerosis.
The immunomodulating substances used so far did mostly not prove successful in practice. This applies especially for the melanoma therapy. There the immunotherapies so far executed mostly only show moderate response rates of less than 10% and simultaneously significant side effects, for example medicament-induced cases of death in systemic IL-2 therapies in stage IV. Also in fields of infections or autoimmune diseases the currently approved therapies result in significant problems. Despite intensive immunotherapy chronic processes are still the rule, such as for example in hepatitis C or the multiple sclerosis.
In addition, many of the currently used immunomodulators are expensive in their production. They require complex syntheses and purification methods, so finally the provision of larger amounts requires larger investments also for the patient.